It forms intrusive igneous rocks.
Explanation
Igneous rocks are formed by the cooling and solidification of molten rock. Depending on the location where the cooling occurs, igneous rocks are classified into two primary types: Intrusive (Plutonic) and Extrusive (Volcanic).
Detailed Analysis:
- Intrusive Igneous Rocks: When molten magma cools deep inside the Earth's crust, it solidifies slowly. This slow cooling allows large crystals to form. These rocks are known as intrusive or plutonic rocks. Examples include Granite and Diorite. Therefore, It forms intrusive igneous rocks. is correct.
- Extrusive Igneous Rocks: When molten rock (lava) erupts onto the surface and cools rapidly, it forms extrusive rocks. The rapid cooling results in a fine-grained or glassy texture. Examples include Basalt and Obsidian. Therefore, It forms extrusive igneous rocks. is incorrect.
- Sedimentary Rocks: These are formed by the accumulation, compaction, and cementation of sediments (fragments of other rocks, minerals, or organic matter) over long periods, not directly from cooling magma. Therefore, It forms sedimentary rocks. is incorrect.
- Metamorphic Rocks: These are formed when existing rocks (igneous, sedimentary, or metamorphic) are subjected to intense heat and pressure, causing physical or chemical changes without melting. Therefore, It forms metamorphic rocks. is incorrect.
Key Takeaway:
Intrusive igneous rocks form from magma cooling slowly beneath the Earth's surface (large grains), whereas extrusive igneous rocks form from lava cooling rapidly on the surface (fine grains).